These are the SVG Icons bundled with the TigerJS Javascript library most are from the IconMoon project so they are free to use.
There are two ways two use the icons in your project.
First use an image tag setting the name of the icon as one of its classes e.g
< img src="" class="T-icons-abacus" />
Once the page is loaded the image would be replaced inline with the SVG image

The next method is just to use the name of the SVG image as part of the class of a non-image element,
in this case the actual SVG image is inserted as the first Child of the element. when the page loads.
So if we have a span..
< span class="T-icons-add-circle" > span text </span>
When the page loads, the SVG is inserted as a first child of the span so we havethe result as
span text
...
To style the SVG image(s) just add CSS color, width and height styles to the original placeholder element and they would be applied to the SVG images once they are loaded, the SVG files are usually under 3KB and some not even upto one byte so it loads instantaniously.

If you insert dynamic elements in your page after the initial page load, and any of tis elements refrences an SVG image you call the function T.insertSVGIcons();
after inserting your new DOM Node so all referenced SVG Images can be loaded and displayed